There's more than enough room to speculate about whether or not you can trust everything you hear or read about medical marijuana — how widespread it is, how well researched it is, how much evidence there is of its medical value, et cetera. The medical marijuana debate is incredibly contentious, and part of the reason why is because it pits the prospect of a multi-billion-dollar industry against the intense social stigma associated with its use since the 1960s. The U.S. passed marijuana tax legislation in 1937 that has since become irrelevant in the face of the federal Controlled Substances Act of 1970. Canada and the US have had somewhat parallel histories with marijuana, and both countries are in roughly the same position today.

You hear some say that there's no scientific or medical basis for the claim that marijuana is medically beneficial for anyone in particular. You hear others argue the exact opposite, and both sides seem to draw from a wealth of studies and pseudo-established facts. Originally, the true value of marijuana wasn't even medical anyway; it was the use of hemp for virtually all the same purposes that plastic now serves in tandem with textiles, fuel, paper (wood) and cotton. Now both laypeople and experts brandish whole sets of published studies against each other, which begs the question: how can both sides seem so firmly substantiated with scientific evidence?

The Canadian publication, The Globe and Mail, published in recent weeks a scarcely impartial piece on the dearth of research to prove the benefits of medical marijuana. Author Geordon Omand writes from the very top, "There is little to no research to support the supposed benefits of medical cannabis, and what evidence exists suggests that using marijuana as medicine may do more harm than good, family doctors' associations across Canada are telling their members." Three advisories put together by the Alberta College of Family Physicians were disseminated to over 32,000 clinicians, and these advisories essentially sum up the alleged entirety of "scientific literature, or lack thereof," on medicinal marijuana.

Family medicine professor Mike Allan, M.D., at the University of Alberta based in Edmonton says of the content in these advisories, "One thing that was quite consistent was adverse events." He says there was a consistent assessment of negative effects and that "the benefits, even if they're real, are much smaller than what people might anticipate." Three of the most recent publications on the subject in Canada came from physicians who simply explored existing research on medical cannabis. Allan claims that family doctors are even being pressured by patients who ask them about medicinal use.

Allan goes on to describe marijuana as high-risk. Health Canada presents data that shows a large spike in the number of clients who have registered with licensed producers to the tune of 200,000 by June 2017 and obviously much more now. That's around 2.7 times more than the 75,166 clients registered by June 2016. "I think this gives [doctors] some comfort," Allan says of the advisories sent out to so many physicians, "saying, 'Look, here's the evidence. It's actually missing in a lot of places, so I can't give it for conditions X, Y and Z.'"

Allan adds that "Some of the pain studies go for nothing more […] than five, six hours. And this is for chronic pain. It's hard to get a great feel for how someone is going to do long-term on a medicine after five, six hours." He goes on to say that there's only one randomized study that evinces the benefits of medical cannabis use for glaucoma patients, and the study only involved six participants. "We would kind of be putting the cart before the horse if we started to prescribe this without the research," Allan asserts.

Meanwhile in the US, Leafly caps the end of 2017 with a rather lengthy list of "The Top Medical Cannabis Studies of 2017," a two-part series that started with a wealth of studies only focusing on those specifically dealing with CBD. The second installment looks at "cannabis wins beyond CBD." One study published in the International Journal of Drug Policy in April and again by November in PLoS One — two highly reputable journals — asserts that cannabis plays a critical role in the opioid epidemic, which President Trump declared a "national emergency." The study demonstrates that 84 percent of patients who get access to medicinal marijuana use ultimately reduced their opioid prescriptions in comparison to only 45 percent of patients in the control group reducing theirs. The same study broadened that analysis to show that many of the states with the lowest opioid-related overdoses are the states in which medical marijuana has been legalized.

Another study published in Nature Medicine illustrates that low doses of THC promote healthy brain aging. Tested in elderly mice, the study found THC to measurably increase the number of connections hippocampus brain cells formed with each other, which is arguably the main neurological signature of age. A third study shows how cannabis benefits patients with Parkinson's disease by relieving symptoms that have long proven difficult to alleviate — balance and gait impairment, cognitive difficulties, challenges initiating movement as well as incessant tremors. Some 40 Parkinson's patients smoked medicinal cannabis for 19 months (give or take) under the supervision of researchers from Tel Aviv University in Israel, and 82 percent of them reported considerable improvement in the aforementioned symptoms. Plus, 75 percent said it simply improved their general mood, too.

All of these and more studies were simply compiled in the second installment of the Leafly series. The first installment dealt with positive CBD benefits from clinical trials for children with epilepsy and patients with autism (a very common target of many marijuana studies). These represent the tip of the iceberg for the number of marijuana-related studies published every year, and Leafly, a proponent of legalizing medicinal marijuana use, states that these are merely the capstone victories for their side of the argument. Even if every one of the studies they cite is utterly bogus, their mere existence doesn't track with the claim on the part of Dr. Allan that there simply isn't much research out there.

Experts are now suggesting that one of the many reasons that there's so much dissension on the subject of medical marijuana research is the fact that there's no adequate placebo for cannabis. Mark Ware, a researcher from McGill University Health Centre based in Montreal, Canada, said that medical marijuana differs in its journey to legitimacy from other mainstream medications because Big Pharma corporations pay hundreds of millions for clinical trials for other drugs that can use placebos for control groups. For marijuana by contrast, patients often know whether or not they are under the influence of marijuana because they either recognize the high or don't.

"When you think about medications that have been given approval to be sold in pharmacies, that's where most if not all of our medications come from," Ware said. "That model simply does not hold for much of the classical herbal cannabis research, where you're looking for basic claims of efficacy and safety, but not trying to make a formal claim for a product that is going to be patented."